Merge branch 'develop' into mplegendre-multi_pkgsrc_roots

Conflicts:
	lib/spack/spack/cmd/create.py
	lib/spack/spack/cmd/extensions.py
	lib/spack/spack/cmd/fetch.py
	lib/spack/spack/cmd/uninstall.py
	lib/spack/spack/config.py
	lib/spack/spack/database.py
	lib/spack/spack/directory_layout.py
	lib/spack/spack/packages.py
	lib/spack/spack/spec.py

var/spack/repos/builtin/packages/sparsehash/package.py

@@ -0,0 +1,14 @@
+from spack import *
+
+class Sparsehash(Package):
+    """Sparse and dense hash-tables for C++ by Google"""
+    homepage = "https://github.com/sparsehash/sparsehash"
+    url      = "https://github.com/sparsehash/sparsehash/archive/sparsehash-2.0.3.tar.gz"
+
+    version('2.0.3', 'd8d5e2538c1c25577b3f066d7a55e99e')
+
+    def install(self, spec, prefix):
+        configure('--prefix=%s' % prefix)
+
+        make()
+        make("install")